Association of uncertain significance genetic variants with myocardial mechanics and morphometrics in patients with nonischemic dilated cardiomyopathy.

BACKGROUND: Careful interpretation of the relation between phenotype changes of the heart and gene variants detected in dilated cardiomyopathy (DCM) is important for patient care and monitoring. OBJECTIVE: We sought to assess the association between cardiac-related genes and whole-heart myocardial mechanics or morphometrics in nonischemic dilated cardiomyopathy (NIDCM). METHODS: It was a prospective study consisting of patients with NIDCM. All patients were referred for genetic testing and a genetic analysis was performed using Illumina NextSeq 550 and a commercial gene capture panel of 233 genes (Systems Genomics, Cardiac-GeneSGKit®). It was analyzed whether there are significant differences in clinical, two-dimensional (2D) echocardiographic, and magnetic resonance imaging (MRI) parameters between patients with the genes variants and those without. 2D echocardiography and MRI were used to analyze myocardial mechanics and morphometrics. RESULTS: The study group consisted of 95 patients with NIDCM and the average age was 49.7 ± 10.5. All echocardiographic and MRI parameters of myocardial mechanics (left ventricular ejection fraction 28.4 ± 8.7 and 30.7 ± 11.2, respectively) were reduced and all values of cardiac chambers were increased (left ventricular end-diastolic diameter 64.5 ± 5.9 mm and 69.5 ± 10.7 mm, respectively) in this group. It was noticed that most cases of whole-heart myocardial mechanics and morphometrics differences between patients with and without gene variants were in the genes GATAD1, LOX, RASA1, KRAS, and KRIT1. These genes have not been previously linked to DCM. It has emerged that KRAS and KRIT1 genes were associated with worse whole-heart mechanics and enlargement of all heart chambers. GATAD1, LOX, and RASA1 genes variants showed an association with better cardiac function and morphometrics parameters. It might be that these variants alone do not influence disease development enough to be selective in human evolution. CONCLUSIONS: Combined variants in previously unreported genes related to DCM might play a significant role in affecting clinical, morphometrics, or myocardial mechanics parameters.

Chronic sleep fragmentation reduces left ventricular contractile function and alters gene expression related to innate immune response and circadian rhythm in the mouse heart.

Sleep disorders have emerged as a widespread public health concern, primarily due to their association with an increased risk of developing cardiovascular diseases. Our previous research indicated a potential direct impact of insufficient sleep duration on cardiac remodeling in children and adolescents. Nevertheless, the underlying mechanisms behind the link between sleep fragmentation (SF) and cardiac abnormalities remain unclear. In this study, we aimed to investigate the effects of SF interventions at various life stages on cardiac structure and function, as well as to identify genes associated with SF-induced cardiac dysfunction. To achieve this, we established mouse models of chronic SF and two-week sleep recovery (SR). Our results revealed that chronic SF significantly compromised left ventricular contractile function across different life stages, leading to alterations in cardiac structure and ventricular remodeling, particularly during early life stages. Moreover, microarray analysis of mouse heart tissue identified two significant modules and nine hub genes (Ddx60, Irf9, Oasl2, Rnf213, Cmpk2, Stat2, Parp14, Gbp3, and Herc6) through protein-protein interaction analysis. Notably, the interactome predominantly involved innate immune responses. Importantly, all hub genes lost significance following SR. The second module primarily consisted of circadian clock genes, and real-time PCR validation demonstrated significant upregulation of Arntl, Dbp, and Cry1 after SF, while subsequent SR restored normal Arntl expression. Furthermore, the expression levels of four hub genes (Ddx60, Irf9, Oasl2, and Cmpk2) and three circadian clock genes (Arntl, Dbp, and Cry1) exhibited correlations with structural and functional echocardiographic parameters. Overall, our findings suggest that SF impairs left ventricular contractile function and ventricular remodeling during early life stages, and this may be mediated by modulation of the innate immune response and circadian rhythm. Importantly, our findings suggest that a short period of SR can alleviate the detrimental effects of SF on the cardiac immune response, while the influence of SF on circadian rhythm appears to be more persistent. These findings underscore the importance of good sleep for maintaining cardiac health, particularly during early life stages.

Left Ventricular Gene Expression in Heart Failure With Preserved Ejection Fraction-Profibrotic and Proinflammatory Pathways and Genes.

BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) is increasingly prevalent and has few treatments. The molecular mechanisms and resultant signaling pathways that underlie the development of HFpEF are poorly defined. It has been proposed that activation of proinflammatory pathways plays a role in the development of cardiac fibrosis. The signature of gene expression (transcriptome) of previously validated left ventricular biopsies obtained from patients with HFpEF and matched referent controls allows for an unbiased assessment of proinflammatory and profibrotic signaling pathways and genes. METHODS: Epicardial left ventricular biopsies from stringently selected HFpEF patients (HFpEF, n=16) and referent control patients (CTR, n=14) were obtained during aortocoronary bypass surgery. The subepicardial myocardium was flash-frozen to build a repository that was parallel-processed for RNA sequencing to allow for an unsupervised in-depth comparison of the left ventricular transcriptome. RESULTS: The average patient age was 67±10 years. When compared with controls, patients with HFpEF were hypertensive with a higher body mass index (kg/m2: 30±5 versus 37±6; P<0.01) and elevated NT-proBNP levels (pg/mL: 155 [89-328] versus 1554 [888-2178]; P<0.001). The transcriptome analysis revealed differential expression of 477 genes many of which were involved in profibrotic pathways including extracellular matrix production and posttranslational modification but no proinflammatory signature. CONCLUSIONS: The transcriptome analysis of left ventricular myocardial samples from patients with HFpEF confirms an overabundant extracellular matrix gene expression, the basis of myocardial fibrosis, without a signature of activated proinflammatory pathways or genes.

Diagnostic yield and predictive value on left ventricular remodelling of genetic testing in dilated cardiomyopathy.

AIMS: We assessed the diagnostic yield of genetic testing and the relationship of left ventricular (LV) reverse remodelling (LVRR) with the presence of DNA pathogenic (P) or likely pathogenic (LP) variants in patients with dilated cardiomyopathy (DCM). METHODS AND RESULTS: From 680 outpatients followed at the Heart Failure Outpatient Clinic of our institution, we selected subjects with a diagnosis of DCM as defined by LV ejection fraction (LVEF) ≤40% and LV dilatation not explained by coronary artery disease or other causes. All patients were offered genetic investigation of 42 disease-associated DCM genes with next-generation sequencing. Seventy patients fulfilled the definition of DCM and 66 underwent genetic investigation. We identified 18 P/LP variants in 16 patients, with a diagnostic yield of 24%. The most common variants were truncating TTN variants (n = 7), followed by LMNA (n = 3), cytoskeleton Z-disc (n = 3), ion channel (n = 2), motor sarcomeric (n = 2), and desmosomal (n = 1) genes. After a median follow-up of 53 months (inter-quartile range 20-111), patients without P/LP variants exhibited higher systolic and diastolic blood pressure, lower plasma brain natriuretic peptide levels, and a larger extent of LVRR, as reflected by the increase in LVEF (+14% vs. +1%, P = 0.0008) and decrease in indexed LV end-diastolic diameter (-6.5 vs. -2 mm/m2 , P = 0.03) compared with patients with P/LP variants. CONCLUSIONS: Our results confirm the high diagnostic yield of genetic testing in selected DCM patients and suggest that identification of P/LP variants in DCM portends poorer LVRR in response to guideline-directed medical therapy.

Urocortin 2 Gene Transfer for Systolic and Diastolic Dysfunction Due to Chronically Increased Left Ventricular Pressure.

We used transverse aortic constriction (TAC) in mice to test the hypothesis that urocortin 2 (Ucn2) gene transfer would increase left ventricular (LV) systolic and diastolic function in the pressure-stressed LV. Three groups were studied: (1) control mice (no TAC); (2) mice that received saline 6 weeks after TAC; and (3) mice that received Ucn2 gene transfer 6 weeks after TAC, using adeno-associated virus 8 encoding murine Ucn2 (AAV8.mUcn2; 2 × 1013 genome copies (gc)/kg, i.v. per mouse). Echocardiography was performed 6 and 12 weeks after TAC. In terminal studies 12 weeks after TAC, rates of LV pressure development and decay and Tau were measured, and LV cardiac myocytes (CMs) were isolated and cytosolic Ca2+ transients and sarcomere shortening rates recorded. Reverse transcription polymerase chain reaction and immunoblotting were used to measure key proteins in LV samples. A CM cell line (HL-1) was used to explore mechanisms. Concentric LV hypertrophy was evident on echocardiography 6 weeks after TAC. Twelve weeks after TAC, LV ejection fraction (EF) was higher in mice that received Ucn2 gene transfer (TAC-saline: 65% ± 3%; TAC-Ucn2: 75% ± 2%; p = 0.01), as was LV peak +dP/dt (1.9-fold increase; p = 0.001) and LV peak -dP/dt (1.7-fold increase; p = 0.017). Tau was more rapid (23% reduction, p = 0.02), indicating improved diastolic function. The peak rates of sarcomere shortening (p = 0.002) and lengthening (p = 0.002) were higher in CMs from TAC-Ucn2 mice, and Tau was reduced (p = 0.001). LV (Ser-16) phosphorylation of phospholamban (PLB) was increased in TAC-Ucn2 mice (p = 0.025), and also was increased in HL-1 cells treated with angiotensin II to induce hypertrophy and incubated with Ucn2 peptide (p = 0.001). Ucn2 gene transfer in TAC-induced heart failure with preserved ejection fraction increased cardiac function in the intact LV and provided corresponding benefits in CMs isolated from study animals, including increased myofilament Ca2+ sensitivity during contraction. The mechanism includes enhanced CM Ca2+ handling associated with increased (Ser-16)-PLB.

Effects of idiopathic erythrocytosis on the left ventricular diastolic functions and the spectrum of genetic mutations: A case control study.

BACKGROUND: We have aimed at exposing left ventricular diastolic functions and the presence of known genetic mutations for familial erythrocytosis, in patients who exhibit idiopathic erythrocytosis. METHODS: Sixty-four patients with idiopathic erythrocytosis (mean age, 46.4 ± 2.7 years) and 30 age-matched healthy subjects were prospectively evaluated. The regions of interest of the erythropoietin receptor, hemoglobin beta-globin, von Hippel-Lindau, hypoxia-inducible factor 2 alpha, and Egl-9 family hypoxia-inducible factor genes were amplified by PCR. Left ventricular (LV) mass was measured by M-mode and 2-dimensional echocardiography. LV diastolic functions were assessed by conventional echocardiography and tissue Doppler imaging. RESULTS: As a result of genetic analyses, genetic mutations for familial erythrocytosis were detected in 5 patients. It has been observed in our study that the risk of cardiovascular disorders is higher in patients. Interventricular septum thickness, left atrial diameter, and some diastolic function parameters such as deceleration time and isovolumetric relaxation time have been found to be significantly higher in idiopathic erythrocytosis group than in the controls. CONCLUSION: This study has shown that LV diastolic functions were impaired in patients with idiopathic erythrocytosis. In this patient group with increased risk of cardiovascular disorders, the frequent genetic mutations have been detected in 5 patients only. Therefore, further clinical investigations are needed as novel genetic mutations may be discovered in patients with idiopathic erythrocytosis because of cardiovascular risk.

Cardiomyocyte-specific Txnip C247S mutation improves left ventricular functional reserve in streptozotocin-induced diabetic mice.

Underlying molecular mechanisms for the development of diabetic cardiomyopathy remain to be determined. Long-term exposure to hyperglycemia causes oxidative stress, which leads to cardiomyocyte dysfunction. Previous studies established the importance of thioredoxin-interacting protein (Txnip) in cellular redox homeostasis and glucose metabolism. Txnip is a highly glucose-responsive molecule that interacts with the catalytic center of reduced thioredoxin and inhibits the antioxidant function of thioredoxin. Here, we show that the molecular interaction between Txnip and thioredoxin plays a pivotal role in the regulation of redox balance in the diabetic myocardium. High glucose increased Txnip expression, decreased thioredoxin activities, and caused oxidative stress in cells. The Txnip-thioredoxin complex was detected in cells with overexpressing wild-type Txnip but not Txnip cysteine 247 to serine (C247S) mutant that disrupts the intermolecular disulfide bridge. Then, diabetes was induced in cardiomyocyte-specific Txnip C247S knock-in mice and their littermate control animals by injections of streptozotocin (STZ). Prolonged hyperglycemia upregulated myocardial Txnip expression in both genotypes. The absence of Txnip's inhibition of thioredoxin in Txnip C247S mutant hearts promoted mitochondrial antioxidative capacities in cardiomyocytes, thereby protecting the heart from oxidative damage by diabetes. Stress hemodynamic analysis uncovered that Txnip C247S knock-in hearts have a greater left ventricular contractile reserve than wild-type hearts under STZ-induced diabetic conditions. These results provide novel evidence that Txnip serves as a regulator of hyperglycemia-induced cardiomyocyte toxicities through direct inhibition of thioredoxin and identify the single cysteine residue in Txnip as a therapeutic target for diabetic injuries.NEW & NORTEWORTHY Thioredoxin-interacting protein (Txnip) has been of great interest as a molecular mechanism to mediate diabetic organ damage. Here, we provide novel evidence that a single mutation of Txnip confers a defense mechanism against myocardial oxidative stress in streptozotocin-induced diabetic mice. The results demonstrate the importance of Txnip as a cysteine-containing redox protein that regulates antioxidant thioredoxin via disulfide bond-switching mechanism and identify the cysteine in Txnip as a therapeutic target for diabetic cardiomyopathy.

miR155 Deficiency Reduces Myofibroblast Density but Fails to Improve Cardiac Function after Myocardial Infarction in Dyslipidemic Mouse Model.

Myocardial infarction remains the most common cause of heart failure with adverse remodeling. MicroRNA (miR)155 is upregulated following myocardial infarction and represents a relevant regulatory factor for cardiac remodeling by engagement in cardiac inflammation, fibrosis and cardiomyocyte hypertrophy. Here, we investigated the role of miR155 in cardiac remodeling and dysfunction following myocardial infarction in a dyslipidemic mouse model. Myocardial infarction was induced in dyslipidemic apolipoprotein E-deficient (ApoE-/-) mice with and without additional miR155 knockout by ligation of the LAD. Four weeks later, echocardiography was performed to assess left ventricular (LV) dimensions and function, and mice were subsequently sacrificed for histological analysis. Echocardiography revealed no difference in LV ejection fractions, LV mass and LV volumes between ApoE-/- and ApoE-/-/miR155-/- mice. Histology confirmed comparable infarction size and unaltered neoangiogenesis in the myocardial scar. Notably, myofibroblast density was significantly decreased in ApoE-/-/miR155-/- mice compared to the control, but no difference was observed for total collagen deposition. Our findings reveal that genetic depletion of miR155 in a dyslipidemic mouse model of myocardial infarction does not reduce infarction size and consecutive heart failure but does decrease myofibroblast density in the post-ischemic scar.

The effect of immune cell-derived exosomes in the cardiac tissue repair after myocardial infarction: Molecular mechanisms and pre-clinical evidence.

After a myocardial infarction (MI), the inflammatory responses are induced and assist to repair ischaemic injury and restore tissue integrity, but excessive inflammatory processes promote abnormal cardiac remodelling and progress towards heart failure. Thus, a timely resolution of inflammation and a firmly regulated balance between regulatory and inflammatory mechanisms can be helpful. Molecular- and cellular-based approaches modulating immune response post-MI have emerged as a promising therapeutic strategy. Exosomes are essential mediators of cell-to-cell communications, which are effective in modulating immune responses and immune cells following MI, improving the repair process of infarcted myocardium and maintaining ventricular function via the crosstalk among immune cells or between immune cells and myocardial cells. The present review aimed to seek the role of immune cell-secreted exosomes in infarcted myocardium post-MI, together with mechanisms behind their repairing impact on the damaged myocardium. The exosomes we focus on are secreted by classic immune cells including macrophages, dendritic cells, regulatory T cells and CD4+ T cells; however, further research is demanded to determine the role of exosomes secreted by other immune cells, such as B cells, neutrophils and mast cells, in infarcted myocardium after MI. This knowledge can assist in the development of future therapeutic strategies, which may benefit MI patients.

The TRIB3 R84 variant is associated with increased left ventricular mass in a sample of 2426 White individuals.

BACKGROUND: Prior studies in animal models showed that increased cardiac expression of TRIB3 has a pathogenic role in inducing left ventricular mass (LVM). Whether alterations in TRIB3 expression or function have a pathogenic role in inducing LVM increase also in humans is still unsettled. In order to address this issue, we took advantage of a nonsynonymous TRIB3 Q84R polymorphism (rs2295490), a gain-of-function amino acid substitution impairing insulin signalling, and action in primary human endothelial cells which has been associated with insulin resistance, and early vascular atherosclerosis. METHODS: SNP rs2295490 was genotyped in 2426 White adults in whom LVM index (LVMI) was assessed by validated echocardiography-derived measures. RESULTS: After adjusting for age and sex, LVMI progressively and significantly increased from 108 to 113, to 125 g/m2 in Q84Q, Q84R, and R84R individuals, respectively (Q84R vs. Q84Q, P = 0.03; R84R vs. Q84Q, P < 0.0001). The association between LVMI and the Q84R and R84R genotype remained significant after adjusting for blood pressure, smoking habit, fasting glucose levels, glucose tolerance status, anti-hypertensive treatments, and lipid-lowering therapy (Q84R vs. Q84Q, P = 0.01; R84R vs. Q84Q, P < 0.0001). CONCLUSIONS: We found that the gain-of-function TRIB3 Q84R variant is significantly associated with left ventricular mass in a large sample of White nondiabetic individual of European ancestry.

Knockdown of ZFAS1 improved the cardiac function of myocardial infarction rats via regulating Wnt/ß-catenin signaling pathway.

Myocardial infarction (MI) is a big health threat in the world, and it is characterized by high morbidity and mortality. However, current treatments are not effective enough, and novel therapeutic strategies need to be explored. ZFAS1 has been proved to be involved in the regulation of MI, but the specific mechanism remains unclear. MI rats were constructed through left anterior descending artery ligation, and hypoxia cell model was also established. The proliferation, invasion, and migration of cells were detected via CCK8, traswell, and wound healing methods. Immunohistochemistry staining, western blotting, and qRT-PCR were used to detect the levels of molecules. Knockdown of ZFAS1 significantly increased the proliferation, migration, and invasion of cardiac fibroblasts. Knockdown of ZFAS1 remarkably improved cardiac function via decreasing infarction ratio and increasing vWF expression, left ventricular ejection fraction, and left ventricular fractional shortening compared with group MI. Knockdown of ZFAS1 also suppressed Wnt/ß-catenin pathway in vivo. The inhibition of Wnt/ß-catenin remarkably reversed the influence of shZFAS1 on cardiac function and cardiac fibroblasts viability. Therefore, Knockdown of ZFAS1 could improve the cardiac function of myocardial infarction rats via regulating Wnt/ß-catenin signaling pathway. The present study might provide new thoughts for the prevention and treatment of MI damage.

Thyroid hormone plus dual-specificity phosphatase-5 siRNA increases the number of cardiac muscle cells and improves left ventricular contractile function in chronic doxorubicin-injured hearts.

Rationale: Doxorubicin is a widely used anticancer drug. However, its major side effect, cardiotoxicity, results from cardiomyocyte loss that causes left ventricle (LV) wall thinning, chronic LV dysfunction and heart failure. Cardiomyocyte number expansion by thyroid hormone (T3) during preadolescence is suppressed by the developmental induction of an ERK1/2-specific dual specificity phosphatase 5 (DUSP5). Here, we sought to determine if a brief course of combined DUSP5 suppression plus T3 therapy replaces cardiomyocytes lost due to preexisting doxorubicin injury and reverses heart failure. Methods: We used in vivo-jetPEI to deliver DUSP5 or scrambled siRNA to ~5-week-old C57BL6 mice followed by 5 daily injections of T3 (2 ng/µg body weight). Genetic lineage tracing using Myh6-MerCreMer::Rosa26fs-Confetti mice and direct cardiomyocyte number counting, along with cell cycle inhibition (danusertib), was used to test if this treatment leads to de novo cardiomyocyte generation and improves LV contractile function. Three doses of doxorubicin (20 µg/g) given at 2-weekly intervals, starting at 5-weeks of age in C57BL6 mice, caused severe heart failure, as evident by a decrease in LV ejection fraction. Mice with an ~40 percentage point decrease in LVEF post-doxorubicin injury were randomized to receive either DUSP5 siRNA plus T3, or scrambled siRNA plus vehicle for T3. Age-matched mice without doxorubicin injury served as controls. Results: In uninjured adult mice, transient therapy with DUSP5 siRNA and T3 increases cardiomyocyte numbers, which is required for the associated increase in LV contractile function, since both are blocked by danusertib. In mice with chronic doxorubicin injury, DUSP5 siRNA plus T3 therapy rebuilds LV muscle by increasing cardiomyocyte numbers, which reverses LV dysfunction and prevents progressive chamber dilatation. Conclusion: RNA therapies are showing great potential. Importantly, a GMP compliant in vivo-jetPEI system for delivery of siRNA is already in use in humans, as is T3. Given these considerations, our findings provide a potentially highly translatable strategy for addressing doxorubicin cardiomyopathy, a currently untreatable condition.

Long-term outcomes of autologous skeletal myoblast cell-sheet transplantation for end-stage ischemic cardiomyopathy.

We evaluated the cardiac function recovery following skeletal myoblast cell-sheet transplantation and the long-term outcomes after applying this treatment in 23 patients with ischemic cardiomyopathy. We defined patients as "responders" when their left ventricular ejection fraction remained unchanged or improved at 6 months after treatment. At 6 months, 16 (69.6%) patients were defined as responders, and the average increase in left ventricular ejection fraction was 4.9%. The responders achieved greater improvement degrees in left ventricular and hemodynamic function parameters, and they presented improved exercise capacity. During the follow-up period (56 ± 28 months), there were four deaths and the overall 5-year survival rate was 95%. Although the responders showed higher freedom from mortality and/or heart failure admission (5-year, 81% versus 0%; p = 0.0002), both groups presented an excellent 5-year survival rate (5-year, 93% versus 100%; p = 0.297) that was higher than that predicted using the Seattle Heart Failure Model. The stepwise logistic regression analysis showed that the preoperative estimated glomerular filtration rate and the left ventricular end-systolic volume index were independently associated with the recovery progress. Approximately 70% of patients with "no-option" ischemic cardiomyopathy responded well to the cell-sheet transplantation. Preoperative renal and left ventricular function might predict the patients' response to this treatment.

Shared genetic pathways contribute to risk of hypertrophic and dilated cardiomyopathies with opposite directions of effect.

The heart muscle diseases hypertrophic (HCM) and dilated (DCM) cardiomyopathies are leading causes of sudden death and heart failure in young, otherwise healthy, individuals. We conducted genome-wide association studies and multi-trait analyses in HCM (1,733 cases), DCM (5,521 cases) and nine left ventricular (LV) traits (19,260 UK Biobank participants with structurally normal hearts). We identified 16 loci associated with HCM, 13 with DCM and 23 with LV traits. We show strong genetic correlations between LV traits and cardiomyopathies, with opposing effects in HCM and DCM. Two-sample Mendelian randomization supports a causal association linking increased LV contractility with HCM risk. A polygenic risk score explains a significant portion of phenotypic variability in carriers of HCM-causing rare variants. Our findings thus provide evidence that polygenic risk score may account for variability in Mendelian diseases. More broadly, we provide insights into how genetic pathways may lead to distinct disorders through opposing genetic effects.

IDH1/2 mutations in acute myeloid leukemia patients and risk of coronary artery disease and cardiac dysfunction-a retrospective propensity score analysis.

Clonal hematopoiesis of indeterminate potential (CHIP) is linked to leukemia gene mutations and associates with an increased risk for coronary artery disease and poor prognosis in ischemic cardiomyopathy. Two recurrently mutated genes in CHIP and adult acute myeloid leukemia (AML) encode for isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2). Global expression of mutant IDH2 in transgenic mice-induced dilated cardiomyopathy and muscular dystrophy. In this retrospective observational study, we investigated whether mutant IDH1/2 predisposes to cardiovascular disease in AML patients. Among 363 AML patients, IDH1 and IDH2 mutations were detected in 26 (7.2%) and 39 patients (10.7%), respectively. Mutant IDH1 patients exhibited a significantly higher prevalence of coronary artery disease (26.1% vs. 6.4%, p = 0.002). Applying inverse probability-weighting analysis, patients with IDH1/2 mutations had a higher risk for a declining cardiac function during AML treatment compared to IDH1/2 wild type patients [left ventricular ejection fraction pretreatment compared to 10 months after diagnosis: 59.2% to 41.9% (p < 0.001) vs 58.5% to 55.4% (p = 0.27), respectively]. Mechanistically, RNA sequencing and immunostaining in hiPS-derived cardiomyocytes indicated that the oncometabolite R-2HG exacerbated doxorubicin mediated cardiotoxicity. Evaluation of IDH1/2 mutation status may therefore help identifying AML patients at risk for cardiovascular complications during cytotoxic treatment.

Beta-adrenergic receptors gene polymorphisms are associated with cardiac contractility and blood pressure variability.

Beta-adrenergic receptors (beta-ARs) play a pivotal role in the cardiovascular regulation. In the human heart beta1- and beta2-ARs dominate in atria as well as in ventricle influencing heart rate and myocardial contractility. Some single nucleotide polymorphisms (SNPs) of beta-ARs might influence cardiovascular function. However, the influence of beta-AR genes SNPs on hemodynamic parameters at rest and their reactivity under stress is still not well known. We aimed to explore the associations between four selected beta-ARs gene polymorphisms and selected cardiovascular measures in eighty-seven young healthy subjects. While in beta1-AR polymorphism rs1801252 no significant association was observed, second beta1-AR polymorphism rs1801253 was associated with decreased cardiac output and cardiac index during all phases and with decreased flow time corrected and ejection time index at rest and during mental arithmetics. Polymorphism rs1042713 in beta2-AR was associated with alterations in blood pressure variability at rest and during head-up-tilt, while rs1042714 was associated predominantly with decreased parameters of cardiac contractility at rest and during mental arithmetics. We conclude that complex analysis of various cardiovascular characteristics related to the strength of cardiac contraction and blood pressure variability can reveal subtle differences in cardiovascular sympathetic nervous control associated with beta-ARs polymorphisms.

Hemodynamic and transcriptomic studies suggest early left ventricular dysfunction in a preclinical model of severe mitral regurgitation.

OBJECTIVE: Primary mitral regurgitation is a valvular lesion in which the left ventricular ejection fraction remains preserved for long periods, delaying a clinical trigger for mitral valve intervention. In this study, we sought to investigate whether adverse left ventricular remodeling occurs before a significant fall in ejection fraction and characterize these changes. METHODS: Sixty-five rats were induced with severe mitral regurgitation by puncturing the mitral valve leaflet with a 23-G needle using ultrasound guidance. Rats underwent longitudinal cardiac echocardiography at biweekly intervals and hearts explanted at 2 weeks (n = 15), 10 weeks (n = 15), 20 weeks (n = 15), and 40 weeks (n = 15). Sixty age- and weight-matched healthy rats were used as controls. Unbiased RNA-sequencing was performed at each terminal point. RESULTS: Regurgitant fraction was 40.99 ± 9.40%, with pulmonary flow reversal in the experimental group, and none in the control group. Significant fall in ejection fraction occurred at 14 weeks after mitral regurgitation induction. However, before 14 weeks, end-diastolic volume increased by 93.69 ± 52.38% (P < .0001 compared with baseline), end-systolic volume increased by 118.33 ± 47.54% (P < .0001 compared with baseline), and several load-independent pump function indices were reduced. Transcriptomic data at 2 and 10 weeks before fall in ejection fraction indicated up-regulation of myocyte remodeling and oxidative stress pathways, whereas those at 20 and 40 weeks indicated extracellular matrix remodeling. CONCLUSIONS: In this rodent model of mitral regurgitation, left ventricular ejection fraction was preserved for a long duration, yet rapid and severe left ventricular dilatation, and biological remodeling occurred before a clinically significant fall in ejection fraction.

Dilated cardiomyopathy caused by truncating titin variants: long-term outcomes, arrhythmias, response to treatment and sex differences.

BACKGROUND: Truncating variants in titin (TTNtv) are the most common cause of dilated cardiomyopathy (DCM). We evaluated the genotype-phenotype correlation in TTNtv-DCM, with a special focus on long-term outcomes, arrhythmias, response to treatment and sex-related presentation. METHODS: Data on patient characteristics and outcomes were collected retrospectively from electronic health records of patients genotyped at two Danish heart transplantation centres. RESULTS: We included 115 patients (66% men). At diagnosis of DCM, mean age was 46±13 years and left ventricular ejection fraction (LVEF) was 28%±13%. During a median follow-up of 7.9 years, 26% reached a composite outcome of left ventricular assist device implantation, heart transplantation or death. In 20% an arrhythmia preceded the DCM diagnosis. In total, 43% had atrial fibrillation (AF) and 23% had ventricular arrhythmias. Long-term left ventricular reverse remodelling (LVRR; LVEF increase ≥10% points or normalisation) was achieved in 58% and occurred more frequently in women (72% vs 51%, p=0.042).In multivariable proportional hazards analyses, occurrence of LVRR was a strong independent negative predictor of the composite outcome (HR: 0.05 (95% CI 0.02 to 0.14); p<0.001). Female sex independently predicted lower rates of ventricular arrhythmias (HR: 0.33 (95% CI 0.11 to 0.99); p=0.05), while the location of the TTNtv was not associated with cardiovascular outcomes. CONCLUSION: DCM caused by TTNtv presented in midlife and was associated with a high burden of AF and ventricular arrhythmias, which often preceded DCM diagnosis. Furthermore, LVRR occurred in a high proportion of patients and was a strong negative predictor of the composite outcome. Female sex was positively associated with occurrence of LVRR and longer event-free survival.

Phenotypic expression and clinical outcomes in a South Asian PRKAG2 cardiomyopathy cohort.

The PRKAG2 syndrome is a rare autosomal dominant phenocopy of sarcomeric hypertrophic cardiomyopathy (HCM), characterized by ventricular pre-excitation, progressive conduction system disease and left ventricular hypertrophy. This study describes the phenotype, genotype and clinical outcomes of a South-Asian PRKAG2 cardiomyopathy cohort over a 7-year period. Clinical, electrocardiographic, echocardiographic, and cardiac MRI data from 22 individuals with PRKAG2 variants (68% men; mean age 39.5 ± 18.1 years), identified at our HCM centre were studied prospectively. At initial evaluation, all of the patients were in NYHA functional class I or II. The maximum left ventricular wall thickness was 22.9 ± 8.7 mm and left ventricular ejection fraction was 53.4 ± 6.6%. Left ventricular hypertrophy was present in 19 individuals (86%) at baseline. 17 patients had an WPW pattern (77%). After a mean follow-up period of 7 years, 2 patients had undergone accessory pathway ablation, 8 patients (36%) underwent permanent pacemaker implantation (atrio-ventricular blocks-5; sinus node disease-2), 3 patients developed atrial fibrillation, 11 patients (50%) developed progressive worsening in NYHA functional class, and 6 patients (27%) experienced sudden cardiac death or equivalent. PRKAG2 cardiomyopathy must be considered in patients with HCM and progressive conduction system disease.